Methods of manufacturing caseless ammunition for air ignition systems



United States Patent Inventor Appl. No.

Filed Patented Assignee Jules Edmond Van Langenhoven Benton County,Arkansas July 18, 1968 Division of Ser. No. 473,556,

July 7, 1965, which is a continuation-inpart of Ser. No. 189,621, Apr.23, 1962, abandoned.

Dec. 8, 1970 Victor Comptometer Corporation Chicago, Illinois acorporation of Illinois.

METHODS OF MANUFACTURING CASELESS AMMUNITION FOR AIR IGNITION SYSTEMS 21Claims, 5 Drawing Figs.

149/18, 96,100:264/3, 3(A). 3(B). 3(C). 3(E) [56] References CitedUNITED STATES PATENTS 702,208 6/1902 102/38 2.230.106 1/1941 264/3(E)2,261,630 11/1941 264/3(B) 2,381,468 8/1945 149/96 2,771,352 11/1956149/100 3,163,567 12/1964 264/3(E) FOREIGN PATENTS 1,755 AD/1894 GreatBritain 89/7 Primary Examiner-Benjamin A. Borchelt AssistantExaminer-Stephen C. Bentley Att0rneyHarness, Dickey & Pierce ABSTRACT:Caseless ammunition, propellant, and methods of manufacturethereofcomprising a lead projectile to which a relatively large solidone-piece porous homogenous nitrocellulose colloid is attached aftermixing nitrocellulose and nitrocellulose solvent and a filler to form awet doughy mixture of colloided nitrocellulose and filler of particularsize and amount providing a predetermined degree of porosity and fromwhich a relatively large one piece body of colloided nitrocellulose andfiller is formed into a size and shape corresponding to the size andshape of the caseless ammunition propellant with the tiller beingthereafter removed from the formed body.

METHODS OF MANUFACTURING CASELESS AMMUNITION FOR AIR IGNITION SYSTEMSThis application is a division of my copending Pat. application Ser. No.473,556, filed Jul. 7, 1965, which is a continuation-in-part of my priorapplication Ser. No. 189,621, filed Apr. 23, 1962, now abandoned.

This invention relates to air operated projectile firing apparatus, andmore particularly to new and improved means of imparting energy to aprojectile for use therewith.

The possibility of using high temperature compressed air to ignite acombustible material, including gun powder, has previously beensuggested. Perhaps the best known example of the use of high temperaturecompressed air for ignition of a combustible material is in internalcombustion engines in accordance with the well-known diesel engineprinciples. Attempts have been made to apply these principles to gunapparatus. For example, in order to increase the projectile velocity inair guns, it has been previously proposed to provide air gun apparatuswith a liquid propellant which may be vaporized and ignited during anair compressing stroke of the gun apparatus. In such apparatus, a supplyof liquid propellant is connected to the air compression chamber throughsuitable delivery means which may include a suitable valve mechanism.When the gun is actuated, a propellant charge is delivered by the valvemechanism to the compression chamber. As the piston in the compressionchamber is rapidly moved by a spring means, or the like, to reduce thevolume of the compression chamber and compress the air therein, the airtemperature and pressure rise to a point at which the liquid propellantis vaporized and ignited. The projectile is commonly supported in directcommunication with the compression chamber and is driven out of thebarrel by the energy released when the liquid propellant is ignited. Inapparatus of this type, the air compression chamber and the ignitionchamber are one and the same. Consequently, any deleterious products ofcombustion are deposited in the air compression chamber, on the piston,and on the associated valves. Furthermore, the piston is movablerearwardly in response to increased pressures caused by theignition ofthe propellant so that a nonrigid reaction wall forms a part of theignition chamber.

The use of an ignition charge ignitable by compression in a compressionchamber and then delivered to a firing chamber to ignite a solidpropellant, such as gun powder, associated with a projectile in the gun,hasalso been suggested. In one prior art disclosure, ignition of acharge of high test gasoline by compression of an air gas mixture in acompression chamber directly connected to a projectile chamber has beensuggested. It has been further suggested that a propellant associatedwith the projectile may be ignited by the ignited charge of gasoline.

Although the present invention may appear to have certain similaritiesto the aforediscussed apparatus, those skilled in the art to which thisinvention relates will readily appreciate that the distinctivecharacteristics and the improved results attained by the presentinvention are substantially different than the prior art.

It is an object of the invention to provide new and improved propellantsfor use with air ignition apparatus and methods of making suchpropellants.

A further object is to provide new and improved propellant andprojectile combinations.

The foregoing objects, and others, have been attained by the applicationof the invention principles of the present invention to air ignitionsystem ammunition as hereinafter disclosed by reference to illustrativeembodiments of the invention shown on the accompanying drawings wherein:

FIG. 1 is an enlarged sectional view ofone form of ammunition suitablefor use with air ignition system apparatus; FIG. 2 is an enlarged sideelevational view ofa round of caseless ammunition suitable for use withair ignition apparatus;

FIG. 3 is an enlarged side elevational view of another round of caselessammunition hot air ignition means of the present invention;

FIG. 4 is an enlarged side elevational view, partly in section, ofanother form of ammunition; and.

FIG. 5 is an enlarged side elevational view, partly in section, of analternative form ammunition.

While certain features of the present invention are particularly welladapted for use in air guns, it will be readily appreciated by thoseskilled in the art to which this invention relates that the inventiveprinciples are also applicable to other devices such as power actuatedtools. Also, while certain forms of the ammunition are particularlyadvantageous in certain applications, the projectile design and themanner of attaching the propellant thereto may be varied as necessaryand desirable depending upon such factors as the velocities required,breech pressures attained, the type of gun, and the projectilepropellant characteristics.

A round of ammunition 110, FIG. 1, adapted for use with air ignitionsystem apparatus comprises a lead projectile, or the like, having afront end portion 112 and a rear end portion 114. In the illustrativeembodiment, the projectile is provided with an inwardly extending bore116. The rear end portion 114 is slightly outwardly flared as indicatedat 118 for abutting obturating. engagement with a similarly contouredportion in a gun barrel. The amount of taper is dependent upon the shotstart force desired. With a propellant, the shot start force should besufficient to hold the projectile in place during the compression strokeuntil the propellant is ignited. In an air propulsion system, theprojectile could be modified to provide a lesser shot start force sothat movement would begin at the beginning of the compression stroke.Bore 116 has a corresponding inwardly directed taper 119 as shown. Thebore 116 provides a propellant storage and ignition chamber within whichone or more propellant caps 120, 121 may be provided. In the embodimentshown, a pair of spaced propellant caps are illustrated. The propellantcaps may comprise a nitrocelluloseproduct which is ignitable under theeffects of heat and pressure to create high energy. The caps have adisclike form which is readily insertable into the bore 116. The capshave a diameter slightly smaller than the open end of the bore 116 sothat they may be pushed along the tapered surface 119 of the bore untilthey are firmly wedged in the ignition chamber provided thereby.

Although the caps may be me made from any material which is adapted tobe decomposed at a high temperature to produce an explosive or gasevolving action Na which may be readily packaged, stored, and handled ina reliable manner, exceptional results are obtained from a porousnitrated cotton product. Nitrocellulose is particularly well suited forthis use. A formula for and a method of manufacturing a suitablenitrated cotton product comprises the following steps and procedures; acommercially available cotton may be prepared for nitration by mixingthe cotton in a solution of H 0 and Na 2 Cp The mixture is boiled forapproximately one hour and the solution level is maintained by theaddition of hot water as necessary. A suitable proportion is 50 grams ofsterile blenched dry cotton; two liters H 0, and 5 grams Na CO After thecotton has been suitably prepared, it should be rinsed thoroughly. Waterat approximately 59 F. may be added to the bottom of the tank in whichthe cotton has been boiled. Cotton should be held under the water duringrinsing and the rinsing operation should continue until pH of 7 isattained. If necessary, a second rinse may be utilized to insure thatthe cotton is thoroughly cleaned. Then the cotton should be subjected toa centrifuging action or the like, to remove most of the water. Then thecotton should be dried, for example, in an oven at approximately F.

After the cotton has been suitably prepared, it is nitrated by mixing ina solution of nitric acid, sulfuric acid, and potassium nitrate. Thenitric acid is first added. to the sulfuric acid and mixed atapproximately 41 F. and care should be taken to keep the temperaturebelow approximately 59 F. while mixing. Then the potassium nitrate isadded and density, temperature is maintained below 50 F. A suitableformula is 148 grams of nitric acid, 1.48 density, 452 grams sulfuricacid, 1 .842 density, and 69 grams potassium nitrate.

After the nitration solution has been prepared, the dry cotton is addedto and mixed in the solution. Again the solution 70should be maintainedat approximately 59 F. and 77cotton temperature should beat about 68--77F. In a nitration formula as described above, approximately 22.3 gramsof the dry cotton is added to the 669 grams of the nitrating solution.The cotton should be soaked in the nitrating solution for approximatelylO hours with the temperature being maintained below approximately 77 F.After the cotton has been soaked in the nitrating solution, the cottonis removed from the solution and rinsed in pure water until a pH of 7 isagain obtained. Then the nitrated cotton may be subjected to the actionof a centrifuge and dried at 77 Fund] a moisture content ofapproximately 7 percent is obtained.

With the aforedescribed nitrated cotton product, the caps are veryporous, easily ignited, completely burned upon ignition, and noundesirable residues are left in the barrel or the associated parts ofthe gun. While in most instances, the propellant may be manufactured,stored, and used in a solid stable form, it may be desirable, in someinstances cases, to cover the propellant discs with a thin plastic likefilm over the entire periphery. The plastic like film may take variousforms and, for example, be provided by the nitrating solution itself.

Another aspect of the invention relates to hot air ignition of apropellant associated with a projectile. The temperature attained by thecompressed air in an air gun, which is directly related to the pressureattained and heat loss sustained, is sufficient to ignite a chargesuitably associated with a projectile in the gun. In one form, thecharge may be fitted inside a charge cavity provided at the rear of theprojectile and in another form, the charge may be mounted on the rear ofthe projectile. The charge preferably takes the form of one or more capsformed from a substance which is adapted to decompose or burn-under thecombined effect of temperature and pressure. The temperature andpressure of air in the compression chamber is sufiicient to decomposeand burn the material. Particularly advantageous results may be obtainedby the use of a porous nitrocellulose material or a similar explosivemanufactured in pellet or cap form is hereinbefore described.

It is possible with the apparatus of the present invention to utilize anignitable propellant by which a level of energy sufficient forrelatively high velocity propulsion may be obtained. The propellant maybe associated with and carried by the projectile prior to loading of thegun. As previously described, solid nitrocellulose caps 120, 121 may bemounted in a cavity 110 provided in the end of the projectile. The capsare ignitable when subjected to high temperatures, and when ignitedprovide a high energy source for projectile propulsion. In general,while certain propellants might be ignitable at lower temperatures, itis desirable to provide compression means by which temperatures in therange of 400 F. to 700 F. are attainable.

Caseless rounds of ammunition,indicated generally by the referencenumeral 301, are shown in detail in FIGS. 2 and 3. In the presentlypreferred form of the invention, each round 301 comprises a metallic(e.g. lead) slug having a generally cylindrical section 302,complementary in diameter to the gun bore, and an end section 303. Abeveled section 304, connecting sections 302 and 303, is adapted toabuttingly engage a beveled section of a projectile cavity in thefirearm. The diameter of the cylindrical portion 302 is sufficientlylarger than the diameter of the firearm bore so as to form a seal and tohold the projectile in place in the ammunition chamber until thepropellant has been ignited and sufficient force is obtained to compressthe lead projectile and force it into and down the firearm bore.

Propellant attaching means are provided in the form of a stub shaftportion 305, integrally connected to the cylindrical section 302, andterminating in a radially displaced upset portion 306. In the presentlypreferred embodiment of the invention, a disc of solid propellant 307, acorresponding in diameter to a cylindrical section 302, is fixed to thestub shaft portion and held in place by upset v portion 306. While thepresently preferred manner of associating the propellant with theprojectile provides particularly advantageous results, it iscontemplated that the propellant might be otherwise attached such as bydirectly bonding the propellant the rear of the projectile withoututilizing the post 305. In the preferred embodiment, the length of thepropellant portion is approximately equal to the length of the mainportions of the projectile. The propellant 307 may be of any type, whichis sufficiently porous to be ignitable by surface contact with hightemperature air such as compressed within the firing chamber 296 by theair compression unit 225, as will become more apparent as thisdiscription proceeds. The propellant 307 may be made pro jectile. Thelayers may have successively higher ignition points progressing towardthe projectile to provide a neater thrust if so desired or may beotherwise varied and modified to attain particular ignition and firingcharacteristics.

In the presently preferred form of the invention, the propellant ismanufactured into a doughy mass suitable for formation in pellet or capform separately from the projectile or directly on the projectile. Thistype of ammunition is caseless and the entire round is fired from thegun without residue.

The propellant made in accordance with the practice of the presentinvention is formed into porous pellets containing as essential elementstherein an ignitable explosive material and a cellulose binder material.

The explosive constituent may consist of any of the wellknownsingle-base, double-base, or triple-base explosive materials consistingprincipally of commercially available nitrocellulose having a degree ofnitration usually from about 13.2 percent to 13.5 percent N and which isalso known as guncotton or smokeless powder. The nitrocelluloseexplosive constituent can be employed in any of the commerciallyavailable forms such as, for example, in the form of fibers (E.G. watersystem) or solvent-softened grains e.g. solvent system), to provide thedesired burning characteristics and porosity of the resultant propellantpellet. In forming nitrocellulose grains, any one of a variety ofsuitable solvents can be satisfactorily employed which are miscible oremulsifiable with water in order to assure uniform distribution thereofand wetting of the nitrocellulose fibers. Solvents which areparticularly suitable for this purpose include acetone, methyl ethylketone, dimethyl ether, diethylene glycol, ethyl glycol, or the like, ofwhich acetone is the preferred solvent. The solvent can be employedeither individually or in mixtures thereof in order to achieve thedesired swelling of the nitrocellulose explosive constituent. So calleddouble-base explosives can also be satisfactorily employed for thepurposes of the present invention by adding nitroglycerins to thenitrocellulose in amounts conventionally ranging from about 5 percent upto about 40 Similarly, triple-base explosives can can be made byadditionally adding nitroguanidine to the nitrocellulose containing thenitroglycerine.

In addition to the explosive constituent, the mixture employed forforming the propellant also includes a water-soluble or water-solventsoluble organic binding agent which is effective to retain the water orwater-solvent employed during formation of a pasty or doughlike mixtureand during the shaping, casting, or extrusion thereof into wet slugs orpellets of the desired shape and size. Subsequently, the a water orwater-solvent is removed to provide the desired porosity. Binding agentswhich have been found particularly suitable for this purpose includecellulose derivatives such as methylcellulose, hydroxyethy] cellulose,carboxymethyl cellulose, carboxyethyl cellulose, starch, arabic gum, orthe like. The quantity of the cellulose binder material employed isdependent on the quantity of water used in the mixture and is controlledin an amount to prevent excessive exudation of the water during theforming or shaping of the wet mixture into slugs. In most instances, thecellulose binder material is employed in amounts ranging from about 3percent up to about 20 percent by weight based on the nitrocelluloseconstituent present, and quantities of about 10 percent by weight arepreferred. On the other hand, the use of the cellulose binder in amountsgreater than about 20 percent by weight has been found to effect anexcessive dilution of the explosive charge, preventing the attainment ofthe desired burning rate and pressure of the explosive when ignited. Itis for this reason that the cellulose binder material is usuallyemployed in amounts ranging from about 3 percent up to about 20 percentby weight.

In addition to the foregoing constituents, any one or combinations ofaccelerators or retardants, as well as stabilizing agents of the typeswell known in the art, can be satisfactorily included to provide therequisite ignition, and rate-of-burn characteristics to the resultantpropellant as well as to enhance its stability during prolonged periodsof storage. Typical accelerating agents include water-free nitrates,while a typical stabilizing agent is represented by diphenylamine.

The mixture of the explosive constituent and binder constituent, whichmay additionally include the accelerating agents, stabilizing agent, or40 retardants as desired, is blended with water or water and solvent inan amount sufficient to form a pastelike or doughy mass which canconveniently be molded, case, or extruded into wet pellets of thedesired configuration and size. The quantity of water employed is notcritical and can be varied consistent with the shaping operationemployed to achieve optimum forming characteristics. The amount of wateror water and solvent employed in the mass does affect the resultantporosity of the propellant formed, since, upon evaporation of the wateror water and solvent from the shaped pellet, voids are formed to agreater or lesser extent which affect the rate of burning of thepropellant. The formation of a uniform wet mixture of the severalconstituents can be conveniently achieved in any one of a variety ofmixing apparatus which preferably are provided with means for preventingor inhibiting the evaporation of water from the mass during mixing.After a substantially uniform wet mass is obtained of the desiredconsistency, the mass can be readily formed, preferably by extrusion,into a plurality of pellets of the desired cross-sectional configurationand of length consistent with its intended end use. The wet pellets aresubsequently dried to effect a vaporization of substantially all of thewater contained therein, in addition to any solvent introduced for thepurpose of gelatinizing the nitrocellulose fibers employed, providingtherewith a dry porous matrix consisting of the nitrocellulose fibers orgranules securely bonded by the cellulose binder. The resultingpropellant can bev repeatedly handled, exposed to varying humidity andnormal temperature conditions, and stored for long periods of timewithout deterioration resulting in loss of explosive power and velocityduring firing.

The conditions of manufacture and use may require additional agents forspecial purposes. For example, the use of a stabilizer, such a asdiphenylamine, is generally advantageous and the use of a dye, with theexception of amine or acid dyes, for coloring the final product may beemployed. A suitable oxidizing agent may be employed to provide betterburning characteristics and suitable breech pressure reducing agents maybe advantageously employed.

One type of propellant suitable for use with the apparatus of thepresent invention is manufactured by use of water to obtain the desireddegree of porosity and is sometimes referred toas a Water System"propellant.

An exemplary formulation of such a Water System" propellant comprises:

200 grams-Nitreellulose (13.35% N;,, 30% water by weight).

1 gram-Diphenylamine.

5 grarns-Hydroxyethyl cellulose (dry).

gramsPotassium nitrate.

5 cc.Castor oil.

grams-Alurninum stearate.

110 cc.-Acetone.

50 cc.-Wa.ter.

The nitrocellulose is a commercial grade (N 13.35 percent l3/45 percent)available from Hercules Powder Company. it

is made from cotton linters with a fineness of to M]. and a viscosity of8 to 20 seconds. It has an ether-alcohol solubility of ll percent and ismanufactured in accordance with MIL-N-244. The diphenylamine is utilizedas a stabilizer as is conventional. The hydroxyethyl cellulose is soldunder the trade name of Natrosol by Hercules Powder Company and has ahigh viscosity (eg 4000 centipoises). It provides a water solublebinder, Other types of water soluble binders might be used such asmethyl cellulose, cellulose monochloracetate, ethyl hydroxeythylcellulose. The potassium nitrate is utilized as an accelerator due toits ability to liberate oxygen during burning of the propellant. Castoroil is utilized for lubricating purposes both in the manufacture of thepropellant during extrusion and in use in the gun. The aluminum stearateacts as an inhibitor or retardant to reduce the rate of burning andbreech pressures. The acetone is a solvent for the water soluble binderand acts with the water for to form a filler, which is subsequentlyremoved to obtain the desired porosity, and to dissolve and disperse thebinder through out the nitrocellulose, the fiber structure of thenitrocellulose remaining substantially unchanged.

The method of mixing and preparing the foregoing formulation comprisesinitially establishing the water content of the wet nitrocellulose andadjusting the water content as necessary to obtain 30 percent water byweight so that the 200 grams of nitrocellulose will contain grams of drynitrocellulose and 60 grams of water. Then 200 grams of the wetnitrocellulose (water wet 30 percent by weight) is added to 5 grams ofthe hydroxyethyl cellulose (dry). The nitrocellulose and hydroxyethylcellulose are mixed by tumbling in a closed container for approximately10 minutes at ll40 F. It is desirable to keep the mix in the containerfor an additional time (i.e. approximately 20 minutes) until the watersoluble binder has begun to swell. Then the mix may be cooled to roomtemperature whereupon the potassium nitrate and the aluminum stearateare added to the mixture. Then the diphenylamine and the castor oil aredissolved in the acetone and added to the mixture. It is then desirableto tumble the mixture in a closed container for about 5 minutes and thentransfer the tumbled mixture to a closed mixer for mixing approximately30 minutes. At this time, it is desirable to add 50 cc of water an mixfor another 30 minutes.

As a result of the foregoing, the water soluble binder is dispersedthroughout the nitrocellulose fibers in a pasty doughy mass and is readyto be molded onto the projectiles. The projectile, of the type shown inFIGS. 2 and 3, is supported with a suitable die enclosing the stub shaftportion and forming a die cavity there around approximately equal to thediameter of the projectile with suitable allowance for shrinkage ad andthe like. The doughy mass is extruded into the die cavity around thestub shaft portion. The propellant dough is confined so that it a cannotflow past the projectile and enough propellant dough is injected to fillthe die cavity and produce the desired length and diameter pellet whendry. The water and acetone are then remove-d by evaporation to producevoids between the cotton fibers resulting in the desired degree ofporosity. A quantity of this propellant equal to 85 mg will propel a .22caliber projectile of 29 grain weight with a muzzle velocity ofapproximately 1,200 feet per second.

If it is desired to produce a lower velocity propellant, the followingformulation may be used:

200 gramsNitroeellulose (13.35% N 30% water by weight).

5 grams-Hydroxyethyl cellulose.

10 grams-Potassium nitrate.

1 gram-Diphenylamine.

ee.Acetone.

85 ec.-Water.

By mixing this formulation as hereinbefore described, a propellantproducing a muzzle velocity of approximately L100 feet per second with a29 grain bullet will be obtained.

This 1,100 feet per second formulation may be used in combination withthe 1,200 feet per second formulation as an ignition charge as shown inFIG. 2. The main charge 307a is extruded onto the projectile first ashereinbefore described. 1mmediately thereafter, the projectile and maincharge are displaced slightly in the die means and the ignition charge307b may be extruded into the rear of the main charge. In the presentlypreferred form, shown in FIG. 2, the ignition charge is centrally placedin the rear of the main charge in a somewhat semispherical formsurrounded with and embedded in the main charge except for an exposedrear surface.

In order to vary the velocity, it may be desirable to change the amountof propellant of any given formulation attached to the projectile.However, it is necessary and desirable to have the dimensions of theammunition remain constant. An inert change may be first extruded ontothe projectile to occupy a portion of the volume of the normalpropellant cavity. An exemplary formulation for the inert chargecomprises:

A technical grade of talcum powder such as that sold by FisherScientific Company has been found to be satisfactory. This mixtureshould be kneaded into a doughy mass for approximately 30 minutes atroom temperature before being extruded. It is important that the inertdough have sufficient consistency to set up on the projectile withouttending to flow past the projectile. In one illustrative arrangement,shown in FIG. 3, producing a velocity of approximately 700 feet persecond with the 1,100 feet per second propellant initially described, avolume of the inert charge 3070 equal to the projectile diameter by 130long is molded onto the rear of the projectile. Then a quantity of the1,100 feet per second propellant 307d equal to the projectile diameterby .090 long is molded onto the rear of the inert charge. This amount ofthe propellant will produce a velocity of approximately 700 feet persecond.

Another type of propellant suitable for use with the apparatus of thepresent invention is manufactured by use of a salt to obtain the desireddegree of porosity and is sometimes referred to as a Salt Systempropellant.

Exemplary formulations of such a Salt System propellant comprises:

A. 100 gramsNitroeellulose (13.3445% N dry).

200 grams-Potassium nitrate (through #100 sieve on #120 sieve). 1gram-Diphenylamine. 100 cc.Acetone. 100 gramsNitrocellulose (13.35.45% Ndry).

300 gramsPotassium nitrate (through #100 sieve on #120 sieve). 1gram-Diphenylamine. 225 cc.-A. cetone. 100 gramsNitrocel1ulose(13.35.45% N dry).

400 gramsPotassium nitrate (through #100 sieve on #120 sieve). 1gramDiphenylamine. 300 cc.Acetone.

The nitrocellulose is a commercially available grade (N 13.35percent13.45 percent) sold by Hercules Powder Company as hereinbeforedescribed. The potassium nitrate is used as a filler which issubsequently removed to produce the desired porosity in the propellant.The diphenylamine is a stabilizer, as is conventional, and the acetoneis a solvent which destroys the fig fiber structure of thenitrocellulose and forms a doughy mass.

The method of mixing and preparing the foregoing propellant formulationscompresses preblending of the diphenylamine and the acetone and thenmixing of the entire formulation in a closed container for about on onehour. The consistency of the propellant may be improved by extruding themass several times. lt is important to maintain uniform extrusion speed.After the final extrusion, which may be the fifth extrusion, theextruded material may be hung to dry at room temperature forapproximately 15 hours to minimize dimensional distortion. Thepropellant material may be extruded in a tubular form. For a propellantof type A, a inch .250 inch nozzle and a .062 inch pin are utilized sothat, after washing and drying, the outside diameter of the propellantwill be about .220 inches and the inside diameter will be about .045inches. When the material has been dried, it is cut to lengths of about.169 inches with a .010 wide slotting saw. A propellant pellet ofapproximately 157 mg is thus provided which, after washing, will weightabout 50 mg. After cutting, the potassium nitrate is removed from thepellets by washing the pellets for approximately four days in slowlyrunning water at about 140 F. Thereafter, the propellant pellets aredried for approximately 24 hours and then the still wet propellant maybe pressed onto the post at the rear of the projectile. The 157 mg (50after washing) pellet of propellant will produce velocities ofapproximately 1,100 feet per second on a projectile weighing 1.93 grams.It is to be understood that the propellant also may be extruded onto theprojectile or molded thereon.

Still another type of propellant suitable for use with the apparatus ofthe present invention is manufactured by use of a solvent in place ofthe water-acetone in the water system to obtain the desired degree ofporosity and is sometimes referred to as a Solvent System." An exemplaryformulation of such a Solvent System propellant comprises:

gramsNitrocellulose (13.35%.45 dry).

1 gram-Diphenylamine.

cc.Toluene.

20 cc.-Alcohol (denatured or isopropylalcohol). 25 cc.-Acetone.

5 gramsAluminum stearate.

5 grams-Ethyl cellulose (high viscosity, K 5000). 1.87 gramsPotassiumnitrate.

The nitrocellulose is a commercially available grade as hereinbeforedescribed. The diphenylamine acts as a stabilizer and the aluminumsterate acts as a retardant to reduce breech pressures. The toluene is aliquid filler by which the desired degree of porosity is attained. Othersuitable liquid fillers include toluene and xylene. The alcohol isutilized to prevent the toluene from reacting with the nitrocellulose.The acetone is utilized to partially react with the nitrocellulosecausing the nitrocellulose to swell and expand without destroying thefiber structure. The ethyl cellulose acts as a binder for the liquids soas to produce a doughy mass. The potassium nitrate acts as anaccelerator producing oxygen during burning.

The method of preparing the propellant comprises mixing the toluene,alcohol, and acetone, and then adding the ethyl.

cellulose and the diphenylamine. This mixture is then thoroughly mixedfor approximately two hours at room temperature so that the ethylcellulose is entirely dispersed in the solvents. Then the drynitrocellulose and all aluminum stearate are added and mixed forapproximately one hour. At this time, the propellant is in the form of adoughy mass ready for molding into a tubular form for subsequentassociation with the projectile or for direct molding onto theprojectile as hereinbefore described. After the molded pellets have beenat room temperature for about 5 minutes, they are boiled in a 2V2percentpotassium nitrate water solution for approximately 15 minutes and arethen dried at F. Boiling of the pellets in the KNO water solutionreduces shrinkage and increases the rate of removal of the solvents toproduce the voids in the propellant. Consequently, no further rinsing isrequired and the remaining KNO will act as an oxidizing agent duringburning of the propellant.

Advantages of these propellants are that they may be economicallymanufactured, they are stable both in manufacture and use under normalconditions, they may be easily associated with a projectile to formcaseless type ammunition,

and they will burn cleanly and minimize corrosion of the gun parts.Furthermore, while being stable and harmless in association with aprojectile during manufacture, storage, and handling, when properlypositioned in a firing chamber of a gun, they are capable of beingignited and generating high energy gases, which when properly confined,are capable of propelling a projectile through a gun barrel at highvelocity. While the propellant attached to the projectile can be ignitedin the open by a flame from a match or the like, the propellant merelyburns at a slow rate causing no movement of the pro jectile and iscompletely harmless. In addition, the propellants and the methods ofmaking them provide versatility and flexibility to enable propellants ofvarying degrees of porosity to be obtained in a manner which is simplerand more economical than previously known.

Referring to FIG. 4, ammunition 730 to be driven from a powder actuatedstud driving comprises a projectile portion in the form of a stud havingan elongated shank portion 732, terminating in a pointed end 733, and aheaded portion 734. A propellant portion of the round of the ammunitioncomprises, in the illustrative embodiment, plug means 738 attached tothe projectile head portion and providing support means 738, obturationmeans 740, and propellant attaching means 742. The plug means may bemade of any suitable material, such as plastic materials, which will becapable of being compressed and driven through the barrel after ignitionof the propellant. 1n the illustrative embodiment, the propellant 744 ismounted in a cavity at the rear of the plug with a surface exposed forsurface contact with high temperature air delivered through passage 706.It will be understood that the propellant may be otherwise attached orassociated with the projectile. Referring now to FIG. 5 an alternativeprojectile form is shown to comprise a threaded head portion 748 withthe plug means 736 being generally cylindrical and molded or extrudedonto the threaded head portion as shown.

In the broadest aspects of the present invention is it contemplated thatother types of propellant may be used and that other propellant ignitionmeans may also be provided. However, particularly advantageous resultsare obtained by the use of the particular propellant and the particularmeans of igni tion the propellant disclosed. Obviously, the details ofconstruction and the arrangement of the parts may be varied withoutdeparting from the principles herein disclosed. Since the inventiveprinciples disclosed herein have obvious application in alternativecombinations, it is intended that the scope of this invention as definedby the appended claims include those alternative embodiments whichutilize the inventive principles herein disclosed.

lclaim:

l. The method of manufacture of caseless ammunition for a firearmcomprising a projectile portion and a relatively large solid one pieceporous ungranulated propellant portion ignitable by surface contact withhigh temperature air comprising the steps of:

l, forming a wet uniformly mixed doughy gelantinized mass of acomposition of nitrocellulose, a nitrocellulose solvent, and a removablefiller;

2. forming a relatively large one piece ungranulated propellant body ofnitrocellulose and removable filler from the wet uniformly mixed doughygelantinized mass, the body being of predetermined size and shape equalto or greater in size than the propellant portion;

3. removing the filler from the ungranulated propellant body to formvoids in the nitrocellulose;

4. hardening and drying the propellant body in ungranulated form whileretaining the voids to provide a desired degree of porosity; and

5. mounting the propellant body in association with the projectilewithout granulation.

2. The invention as defined in claim 1 and the propellant body beingmounted on the projectile portion prior to hardening and drying.

3. The invention as defined in claim 1 and the propellant body beinglarger than the propellant portion, and the propellant portion beingsevered from the propellant body and then mounted on the projectileportion.

4. The method as defined in claim 1 and the composition being formedapproximately in the ratio of 1 part by weight nitrocellulose and 2-4parts by weight of removable tiller.

5. The method as defined in claim 1 and the composition being formedapproximately in the ratio of l part by weight nitrocellulose and 2parts by weight removable filler.

6. The method as defined in claim 1 and the composition being formedapproximately in the ratio of 1 part by weight nitrocellulose and 3parts by weight removable filler.

7. The method as defined in claim 1 and the composition being formedapproximately in the ratio of l by weight nitrocellulose and 4 parts byweight removable filler.

8. The method as defined in claim 1 and the removable filler being asolid particulate material.

9, The method as defined in claim 3 and the solid particulate removablefiller being of predetermined size.

10. The method as defined in claim 9 and the solid particle fillercomprising particles approximately of a size such as to pass through asieve sieve and be retained on a 0120 sieve.

11. The method as defined in claim 1 and the removable filler being aliquid.

12. The method as defined in claim 11 and the composition furtherincluding a cellulose binder.

13. The method as defined in claim 1 and the removable filler beingtoluene.

14. The method as defined in claim 13 and the cellulose solvent beingacetone.

15. The method ad as defined in claim 14 and the composition furthercomprising alcohol.

16. The method ad defined in claim 15 and wherein the toluene, alcohol,and acetone are separately mixed, then a cellulose binder is added andmixed, and then the nitrocellulose is added and mixed.

17. A process for manufacturing a. relatively large ungranulated solidporous firearm propellant body which comprises the steps of: forming awet uniform doughy mass consisting of nitrocellulose, a cellulosesolvent, and a removable filler, forming the wet doughy mass into arelatively large body of ungranulated propellant of a size and shapesuitable for as sociation with a projectile as formed to provide thepropellant charge therefor, and removing at least portions of the fillerfrom the body of ungranulated propellant to form voids and obtain adesired degree of porosity.

18. The method of manufacturing of a porous relatively large one piecesolid propellant of a size and shape by itself forming the charge for afirearm comprising the steps of: wet mixing of nitrocellulose and asoluble nitrocellulose binder and a cellulose solvent and a removablefiller to form a wet pasty doughy mass, wet formation of a propellantbody of the approximate size and shape of said relatively large onepiece propellant having the removable filler dispersed therein,solidification of the cellulose in the propellant body form, and removalof the filler to form voids throughout.

19. The method of producing a relatively large solid porous propellantbody of a size and shape by itself forming the charge for firearmammunition comprising the steps of: Forming a mixture comprisingtoluene, alcohol, acetone, and nitrocellulose into a wet doughy mass;forming the wet doughy mass into a shaped form at least as large as thepropellant body; boiling the shaped form in water to remove the tolueneand alcohol and acetone and form voids; and then drying the shaped formto form a solid porous nitrocellulose propellant body suitable forassociation with a projectile to form ammunition for a firearm.

20. The method of manufacture of caseless ammunition for a firearmcomprising a projectile portion and a propellant portion ignitable bysurface contact with high temperature air comprising the steps of:

1. forming a wet uniformly mixed doughy mass of a composition ofnitrocellulose, a nitrocellulose solvent, and a removable filler;

2. forming a propellant body of predetermined size and shape equal to orgreater in size than the propellant portion from the wet uniformly mixeddoughy mass;

3. removing the filler to form voids in the nitrocellulose;

4. mounting the propellant body on the projectile portion;

5. hardening and drying the propellant body while retaining the voids toprovide a desired degree of porosity.

21. The process of manufacturing caseless ammunition for an air ignitionsystem firearm, said caseless ammunition comprising a projectile portionand a propellant portion, said process comprising the steps of:

1. manufacturing a large hard porous body of ungranulated colloidednitrocellulose by a. mixing nitrocellulose an and a nitrocellulosesolvent and a removable fillerto form a wet extrudable doughy mass ofgelatinized nitrocellulose having the removable filler uniformlydispersed throughout,

b. forming a large body of ungranulated nitrocellulose from the wetextrudable doughy mass and of a size and shape generally correspondingto the size and shape of the propellant portion of the'ammunition andwith the removable filler uniformly dispersed throughout,

0. removing the filler from the large body of ungranulatednitrocellulose to provide a large porous body of nitrocellulose,

d. drying and hardening the large porous body of ungranulatednitrocellulose to provide a large hard porous body of ungranulatedcolloided nitrocellulose; and

2. permanently attaching the large'hard porous body of ungranulatedcolloided nitrocellulose to the projectile without further change in thecomposition or general size of the body with at least one surface ofsaid body being orgy/cred and exposed for direct: Contact with hotignition air. v a

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 545,333 Dated December 8, 1970 flx) Jules E. Van Langenhoven It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 1, lines 74-75, delete "hot air ignition means of the presentinvention". Column 2, lines 52-53, "Na Cp should be --Na CO line 72,delete "density," and insert therefor --the--. Column 3, line 3, delete"70" and insert therefor --temperature, delete "77 and insert therefor--the-; line 20, delete "instances"; line 4'7, '11! should be -116-;line 722, delete "a" (second occurrence). Column line 3, after"propellant" insert --to--; line 11, after "be" insert --of any type,which is sufficiently porous to be ignitable by surface contact withhigh temperature air such as compressed within the firi1 chamber 296 bythe air compression unit 225, as will become more apparent as thisdescription proceeds. The propellant 307 may be made up of a homogeneousmass of propellant material of several 1a; of different propellantmaterial each of which may be molded, extrud or otherwise mounted onthe--, delete "made"; line 13, delete "neat( and insert therefor-greater--; line 34, "E. G. should be --e. g. before 'e. g. (secondoccurrence) insert a parenthesis line after "40" insert delete "can"(second occurrence); line 59, delete "a". Column 5, line 16, delete"40"; line 19, "case" should b --cast--; line 50, after "such" delete"a". Column 6, line 17, delet "for"; line 42, "an" should be --and-;line 50, delete 'ad"; line 52, delete "a". Column 7, line 47, "45%"should be --.45%-; line 51, "10000" should be -160cc--; line 69, delete"fig". Column 8, line I delete "inch" (first occurrence); line 46,delete "toluene" and insert therefor -benzene-; line 58, delete "all".Column 9, line 17, afte "driving" insert --tool--; line 37, "is it"should be --it is--. Colun 10, line 15, after "1 insert --part--; line21, "particle" should be --particulate--, line 23, delete 'sieve" (firstoccurrence), insert before "100", change "0120" to --#120-; line 33,delete "ad"; line E ORM PC3-1050 (10-59) -gc at s us novllmunn nnmnoorncz; nu

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PAG] Patent No. 3,333 Dated December 8, 1970 InventoflX) Jules E. Van Langenhoven It iscertified that error appears in the aboveidentified patent and that saidLetters Patent are hereby corrected as shown below:

"ad" should be --as-. Column 11, line 17, delete "an". In theReferences: "2, 230, 106' should be -2, 230, l00-.

Signed and sealed this 11th day of May 1971.

(SEAL) Attest:

WILLIAM E. SCHUYLER EDWARD M.FLETCHER,JR. Attesting Officer Commissionerof Pat USCOMM-DC E CIFWI PO-IOSO (\O-691 a u.s. sovnmmn "mums omcs; no

